MFGas mass flow controller/How to choose the control mode of the meter

Gas mass flow controller(MThere are various control methods such as simulation, local panel operation, digital communication, etc. The selection of control mode is closely related to the matching of on-site hardware conditions and customer application requirements. At the same time, different choices also have a significant impact on costs. Therefore, when selecting a flow controller, the impact of control mode on procurement costs should be taken into account, provided that basic parameters such as flow pressure are met.

Below is a brief list of common control methods, hardware requirements, and application scenario requirements for customers to refer to when selecting applications

1Simulation control method

The common analog control methods for gas mass flow controllers include voltage output, such as0-5VThe1-5VWait, there are also current type outputs, such as4-20mAThe0-20mAWait. The selection of current or voltage control methods should be comprehensively considered based on their respective advantages, disadvantages, and system requirements. The advantage of voltage type signals is that they are easy to connect and can be read in parallel by multiple devices. The disadvantage is that they are not suitable for long-distance transmission, have ground voltage drop, which can affect detection accuracy, and have weak anti-interference ability; The advantages of current type are strong anti-interference ability and reliable long-distance transmission, but the equipment needs to be one-to-one. If it is a one to many device, it must be connected in series, which will increase the probability of single point failure and introduce the need for isolated signal ports, further increasing system costs.

1.1Gas mass flow controller+secondary meter controller

The secondary meter controller for gas mass flow controller is used forManual setting and real-time displayThe current flow meter is easy to set, convenient to use, and has intuitive display. It is suitable for experimental research situations that do not require frequent setting and adjustment. The entire system is simple and easy to use. Simply connect the air circuit and plug in the power supply, and the system is cost-effective,; Of course, the shortcomings of this system are also very obvious, that isCannot be automatedChanging flow settings according to demand can only be manually adjusted, therefore it is not suitable for automated flow setting changes.

1.2Gas mass flow controller+PLCOr collection card

In industrial application scenarios, customers usually have ready-made production linesPLCEquipment, acquisition card devices, or customer developed signal acquisition boards, through these ready-made devices, customers can easily achieve computer control of gas mass flow controllers through these ports and software configuration/The setting and reading functions of the meter, as well as the automatic flow rate setting and change control according to the process requirements of the production line or automation equipment, in order to achieve the production process goals.

This control system is based on the utilization of existing resources by customers, and the flowmeter is the most cost-effective and can achieve automated control. The disadvantage is that due to the use of analog ports, it usually requires a one-to-one dedicated port design, which can result in high hardware resource overhead. This is more suitable for small-scale applications of several machines. If used on a production line with dozens of devices, hardware port resources are severely consumed, and cost factors need to be considered together. Of course, there are also designs that use hardware port time-division multiplexing to reduce system costs, which is actually a concession to real-time requirements. When setting channels to use time-division multiplexing, it is also necessary to consider the issue of independent signal locking, which will further increase costs.

2Digital communication control method

Digital communication methods such asRS485TheMODBUSAll of them have wide applications. For industrial applications, digital communication is used to integrate software into a computer integrated control software system, enabling one computer to control multiple devices and achieve the goal of automated process control. Due to the use of communication methods, typically such asMODBUSIt can achieve one to many port reuse, with low system hardware overhead, high integration, relatively reliable bus, good universality, low system software development cost, and good maintainability. When selecting this type of flowmeter, it is necessary to consider both the hardware resources of the system and the cost of the gas mass flow controller, and take into account the above factors1.2Conduct a comprehensive cost comparison of the proposed solution and select a product combination with comprehensive advantages.

3Local panel control method

Normally, gas mass flow controllers with local LCD displays will also have a local control panel, which can facilitate changes to the flow setting control of the machine. This type of gas mass flow controller usually combines digital communication and analog control functions, and is a product of gas mass flow controllers. The advantages of this type of gas mass flow controller are obvious, such as rich LCD display content, simple use, and a flow controller that can complete flow control without additional equipment assistance, occupying a small space; Multiple control modes for easy switching, flexible on-site configuration, and more; Of course, in terms of cost, it is relatively the highest, and the advantage is its flexibility in use.

When selecting a gas mass flow controller, there is no doubt that the control method is not the primary determining factor. However, when selecting, when some basic flow parameters are selected, objective hardware conditions, usage requirements, real-time requirements, automatic or manual control, and other conditions are comprehensively evaluated to choose a product for an application scenario.

Guangzhou Dichuan Instrument Co., Ltd. is a high-tech enterprise specializing in the production of gas mass flow controllers and pressure controllers. The company integrates design, development, production, and service, and provides customers with competitive and process suitable solutions based on their different processesGas mass flow controllerGas mass flowmeter, online pressure controller, sealed chamber pressure controller, gas testing control system, leak detection system, mixing system, humidity control system, etc. We insist on continuously innovating based on the actual needs of our customers, creating new products that are suitable for their needs and market demands!